Human beings recognize the surrounding environment using the five senses, such as sight, hearing, smell, state, and touch. Among the five senses, the human being mainly depends on the senses of sight and hearing to acquire information on the surrounding environment. However, in many cases, actually, the human being depends on tactile information to acquire information on the surrounding environment. The sense of touch is used to determine the position, shape, texture, and temperature of an object. Therefore, it is necessary to provide tactile information as well as visual information and auditory information in order to transmit realistic feeling. Therefore, in recent years, haptic technology for providing tactile information together with visual information and auditory information to enable the user to directly interact with a scene on the screen in the fields of education, training, and entertainment has drawn great attention.
The haptic technology provides various information of the virtual or actual environment to the user through tactile feeling and kinesthetic feeling. The term ‘haptic’ is the Greek language meaning the sense of touch, and includes the meaning of tactile feeling and kinesthetic feeling. The tactile feeling provides information on the geometrical shape, roughness, temperature, and texture of a contact surface through skin sensation, and the kinesthetic feeling provides information on a contact force, flexibility, and weight through the propriocetive sensation of muscle, bone, and joint.
In order to provide the tactile information to the user, the following processes are needed: a process of acquiring tactile information; a process of editing or synthesizing the tactile information with, for example, image information; a process of transmitting the edited tactile information and image information; and a process of playing back the transmitted tactile information and image information.
In recent years, many researches on haptic rendering methods of playing back tactile information and haptic devices for displaying the tactile information have been conducted. However, there has not been sufficient research on a technique for acquiring or editing the tactile information and a technique for transmitting the tactile information.
International Publication No. WO2004/003717 discloses a method of calculating a time delay and synchronizing tactile information with image information in connection with the transmission of the tactile information. In addition, Korean Patent Unexamined Publication No. 10-2005-0045700 discloses a technique for synchronizing video/audio packet signals with tactile packet signals and transmitting the packet signals through a multiplexing module. Further, U.S. Published Application No. 2006-129719 discloses a technique for outputting a haptic effect in association with a time slot to assign time and order to the haptic effect signal, thereby outputting the haptic effect with time. U.S. Pat. No. 6,101,530 discloses a technique for transmitting an HTML file including tactile information over a network supporting TCP/IP protocols.
However, the disclosed techniques have difficulties in effectively displaying and transmitting the tactile information. In particular, the disclosures do not have sufficient techniques for encoding the tactile information, combining the tactile information with image information, and transmitting the combined information.
Meanwhile, a kinesthetic display apparatus, such as the PHANToM™ made by SensAble Technologies, Inc., has been generally used to provide haptic information. The kinesthetic display apparatus can display the texture, friction, and shape of a virtual object using a motor or a mechanical structure, such as an exo-skeletal structure. However, the kinesthetic display apparatus is incapable of directly providing information on the skin of the user, and the end-effect of the kinesthetic display apparatus is provided to the user by a pen or a thimble for feeling force. The kinesthetic display apparatus is expensive.